Dietary fermented soybean meal in swine nutrition and effects on regulation of gut health, immune system and environment: a review

In swine diets, fermented soybean meal (FSBM) has become a viable substitute for conventional soybean meal, providing advantages for immune system performance, gastrointestinal health, and environmental effect. This review summarises the data showing that FSBM: improves growth performance by raising the feed conversion ratio (FCR) by 5–10% and the average daily gain (ADG) in weaned piglets by 8–15% as a result of increased nutrient bioavailability. improves gut health by increasing populations of good bacteria (e.g., Lactobacillus spp. ↑ 25–40%) and altering intestinal architecture, such as increasing villus height by 20–30% and decreasing crypt depth by 10–20%. enhances mucosal immunity (e.g., IgA ↑ 20–35%) and reduces pro-inflammatory cytokines (e.g., TNF-α ↓ 15–25%) to support immunological function. contributes to sustainable pig production by reducing environmental effect by 10–20% via nitrogen excretion and 15–30% through ammonia emissions. Pig farmers may improve herd health, performance, and environmental impact by substituting FSBM for traditional soybean meal.